Cara Rose DeFabio started her one-woman show by reminding the audience to keep their phones on.

The audience at the 80-seat Exit Theater in the Tenderloin laughed - but DeFabio was serious.

Throughout her show, "After the Tone," which explored how people talk about death online, DeFabio took pictures of herself, texted with the audience, acted out digital photos and played messages audience members sent to her. While projecting photos and tweets with the #RIP hashtag, she put on all black and told the audience to take her picture.

"Theater is about exploring human emotions, mediated through dialogue. Now dialogue is often a text, a tweet, and it's necessary to show these if we're talking about our relationships," the 33-year-old San Francisco native said after the show. "If we ignore tech, we're also ignoring all the implications, but it's changing our behavior in really interesting ways."

DeFabio is part of a growing group of artists who are using technology, especially cell phones, to integrate audiences into their art. While theater performers have long needed sound technicians, they're now looking for programmers as well. And while aspiring producers might once have gone on to acquire a master's degree in set design, some are going to developer boot camps instead.

"I want the show to be like a search engine," DeFabio said. "Here are images, fragments. This is all the information. You see what floats to the top. There's no narrative, but that's part of the medium. You go on the Internet, and you don't get one story - you get inundated with images and fragments."

The first time DeFabio, a dancer and actress, used technology in her work was by accident in 2008, when she suddenly found herself unable to leave her day job in time to get to the stage for a performance. But after a year of preparation, she wasn't about to miss her own show.

So she Skyped in.

"Necessity is the mother of invention," she said.

Getting technical

A little later, she tried using technology intentionally in her performance piece "She Was a Computer," about her grandmother (who was a "computer" when the term meant a person, usually a woman, who performed computations). She set it up so the audience could interact with her through Google Voice and text messaging. But it was ungainly - she had to hire someone to respond to every text individually - and allowed only limited interaction.

Then she remembered Andrew Hyder, a programmer she'd met a year before at a San Francisco design festival. DeFabio contacted him, and over a beer at the Mission District bar Homestead, DeFabio explained her vision for interactive performances.

"As a performer, you get so much feedback from the audience already - are they laughing, crying, is it loud? - but they don't usually see how their reactions affect the performance," she said. "Technology amplifies it, but I didn't have the skill set."

Coding for the stage

Hyder, a hacker on a fellowship at Code for America, which brings Web skills to civic issues, had his own ideas about how to make it work. "I loved her idea of each show being unique based on who was there," he said. "I wanted to make something repeatable, and something open-platform that other performers can use."

Hyder recruited two other volunteers from Code for America - Richa Agarwal and Shaunak Kashyap - to build an open program for any performance artist who wanted to create audience interaction. "And at night, while she iterated her performance," he said, referring to rehearsals, "we iterated the program."

While DeFabio's performance explores ways people talk about death online, her audience can affect the content. At one point, she asks everyone to leave a message describing an object they carry with them that brings back memories of someone - the messages play back later in the show.

She discusses what happens when people who have saved voice messages from deceased loved ones change phone plans. While taking a photo of herself, she asks the audience if she looks sad enough. And at the end of the performance, everyone gets a text and can have conversations with DeFabio, post-mortem.

Tech inspiration

DeFabio has started going to tech conferences to find out what else might be interesting to add into the show.

At a Twilio conference last week dealing with Web and mobile communication technology, DeFabio and Hyder, 31, attended a discussion on interactive art titled "Communications Turning Viewers into Participants." The first speaker, Benjamin Tomlinson, the creative director of a British company called Poke, told a story about setting up text-activated snow machines in London during Christmas - text to a number, and hidden snow machines begin to blow. He also adjusted an office building so that the lights change color depending on the positive and negative tweets about the company - greenish hue was happy, red was not.

In the audience was artist Dan Hossom, a 27-year-old who lives in the outer Richmond District. Hossom had just finished a nine-week developer boot camp where, instead of learning art skills like metalworking or freehand drawing, he learned a new program language. "I'm finally at the point to where my technical abilities are catching up to my inspiration."

Viewing the future

After the conference session, DeFabio and Hyder sat in the Concourse Exhibition Center lounge, where they talked about future collaborations.

"I want to build something that's accessible to artists everywhere who want to bring the audience into the show," said Hyder, who calls himself an urban hacker. "And do citywide installations with the same principles." Their first run was "a prototype," said DeFabio, for a show they're planning at CounterPulse, a performance venue in SoMa, on Nov. 2. and 3.

"As an artist, how do I reach out to the people with the right skill set?" DeFabio said. "It's not 'oh, I need a lighting designer,' it's 'I need a coder.' "